Comparison of the Effects of Different Rehabilitative Strategies on Reorganization of Motor Cortex After Cortical Microlesions in Primates

Friel, KM(Department of Molecular and Integrative Physiology, University of Kansas Medical Center, USA)Nudo, RJ(Center on Aging and Dept of Molecular and Integrative Physiology, University of Kansas Medical Center, USA)

Previous studies demonstrated that after a microlesion in the hand representation of primary motor cortex (M1), the size of the spared hand representation decreased during spontaneous recovery (i.e., no postinfarct intervention). If the unimpaired hand was restrained and monkeys received repetitive skill training with the impaired hand, the spared hand representation was retained. The goal of the present study was to determine if restriction of the unimpaired hand was sufficient to retain the spared hand representation. After a microlesion in the hand area of M1 in adult squirrel monkeys, the unimpaired hand was restrained, but monkeys did not receive additional rehabilitative training. Motor maps were derived using microelectrode stimulation techniques in anesthetized monkeys before and one month after the microlesions. One month after the lesion, the size of the hand representation and the sizes of component finger and wrist/forearm representations had decreased. The magnitude of the decrease was not different from animals undergoing spontaneous recovery. Hand areas were significantly smaller than in animals that had received daily repetitive training after infarct (p < 0.05). Taken together with previous findings, these results suggest that retention of hand representations within M1 after cortical injury requires repetitive use of the impaired hand after injury.

Back to the top.Presentation Number SAfriel0817Keywords:stroke, motor, cortex, plasticity, physical therapy